1. Technical Field
The present invention relates generally to power supply converter circuitry and, more particularly, to a current-controlled, switching mode power supply converter circuit that is stable in light, medium, and heavy output load conditions.
2. Introduction
Switching mode power supply systems are often implemented in handset equipment to power various components such as, for example, active-matrix organic light-emitting diode (AMOLED) panels. Such applications typically require large current capacity as well as accurate output voltage and low output voltage ripple in order to provide lighting that is comfortable to the human eye. As such, constant-frequency current-mode-controlled converter circuitry is commonly used in this context. When compared to other structures (e.g., voltage-mode-controlled converters, constant-on variable-frequency converters, and constant-off variable-frequency converters), the constant operation frequency of the constant-frequency current-mode-controlled converter circuitry reduces frequency spectrum interference experienced by other circuitry in the system. However, conventional constant-frequency current-mode-controlled converter circuitry is not stable in all output load conditions, oftentimes resulting in the converter oscillating between a discontinuous current mode (DCM) and a continuous current mode (CCM). Therefore, there exists a need for a constant-frequency current-mode-controlled converter circuit that is suitable for handset applications, and is efficient and stable in light, medium, and heavy output load conditions.